Freitag, 23. Oktober 2015

Milestones in herniated disc treatment: Chemonucleolysis 1963

Eugene Jansen and Arnold Ball isolated Chemypapain, a protelyc enzyme, extracted from papaya latex 1941. In 1956, Lewis Thomas injected chemopapain into the ears of a rabitt and recognized that they dropped because the cartilage was decomposed by the chemical substance and lost their hold function.
1963 injected Lyam W. Smith, an orthopedic surgeon and simultaneously owner of Smith Laboratories for the first time Chemypapain between two vertebrae by the posterolateral approach, described by Ottolenghi and Craig for biopsy. Smith called this method "Chemonucleolysis". The chemical substance has been registrated by Smith Laboratories under US. Patent No. 3,320.131 and produced and distributed through Baxter-Travenol Laboratories, Deerfield/Illionois.

Chemical process:

Chemypapain alters the characteristics of the nucleus pulposus by liberation of condroitin sulfate and keratin sulfate by hydrolysis of non collagenous proteins of muscopolysaccharide involvment and leading to polymerization of nucleus pulposus.

Goal of Chemonucleolysis:

The shrinkage of the gelatinous mass within the disc caused by Chemypapain leads to a pressure reduction within the disc and the sinking of the bulging of the anulus fibrosus. Thus reduces the pressure relief of the affected nerve root. Therefore the result is called intradiscal decompression.

Approach and operation technique:

Access path and surgical technique draw on experiences of the intervertebral disc biopsy of Ottolenghi and Craig. The patient is placed either lateral or prone position. By the postero lateral access to the foramen intervertebralis a guidewire is inserted to the center of the disc under bi-planar x-ray control. Subsequently the injection needel is pulled over the guidwire and pushed forward to its tip . The guidewire is removed and by a syringe Chemypapain is injected into the disc. The access diameter is only 2 mm and the opening of the disc closes shortly aterwards.

Necessary technical equipment: X-ray C-arm:

The launch of mobile x-ray device with x-ray and image intensifier technology for bi-planar images by Siemens 1963 with Siretom X-ray C-arm had considerble influence for spreading of biopsy and spinal disc treatment. The safe positioning of guide wire and injection needle is still crucial of a successfull treatment by the posterolateral access to the intervertebral foramen. It is no coincidence that the development of X-ray C-arm machine and the treatment of the disc by the posterolateral access coincide. The development of mobile X-ray C-arm equipment is subject to ongoing changes and improvements to the current state of the art as a mobile 3D robot X-ray machine.

Scientific Documentation:

Smith published his first experiences with Chemonucleolysis in "Journal Of American Medical Association" (JAMA). Subsequently 75 surgeons in the USA and Canada treated 17,000 patients and reported success rates of 83%
According to the study of 104 veterans with herniated disc by the neurosurgeon Bernard J. Sussmann (Walter Reed Military Hospital Washington) who came to a different conclusion the use of Chemypapain for the treatment of herniated discs was eliminated by the FDA within USA in 1975. In Canada, Switzerland and Germany Chemypapain was continously market by Travenol and Chemonucleolysis continue to apply. Many physicians worldwide are still convienced that the treatment is safe, successfull and costeffective and published numerous scientific papers about this operation technique. It is suitable only for treatment of protrusions, as the chemical substance must not leak out of the disc which would happen by treatment of extruded gelatine mass with demaged Anulus Fibrosis.

Treatment of disc protrusion by Chemonucleolysis is controversial. Much physicians prefer conservative treatments.Ultimately, today the well-informed patient is involved in the process of decission what kind of treatment will be applyed, while the duration of healing is an important factor related to his profession and living conditiones.Anyway Chemonucleolysis as a minimally invasive surgery was a first alternate to open surgery by laminectomy and is therefore a milestone in historical prolapsed disc treatment.